Plumb-bob.



L. o. sLoGGETT.

-PLUMB BOB. APrLIoATIoN FILED :mm 2. 190s.

Patented July 20. 19092 y INPE/vraie L4. [gg e if.

NlNn

` Manley L. O. SLUGGETT.

PLUME BOB. APPLIOATION FILED JUNI: s, 190s4 Patented July 20, 1909.

UNITED STATES PATENT OFFICE.

LOUIS O. SLOGGETT, OF CHICAGO, ILLINOIS.

PLUME -B OB no. easter/7.

To all whom 'it 'may concern:

Be it known that I, LoUIs O. Snoeonrfr, citizen of the United cdtiates,residing at Ohicago, in the county of Oooh and Stateof Illinois, haveinvented certain new and useful Improvements in Plumb-Bobs, of which thefollowing is a specification.

This invention is a plumb-bob particularly adapted and intended for usein con nection with transits, theodolites and similar instruments,andhas for its object to pro vide a plumb-bob which will be held in acasing out of the wind, and which accordingly will not be affected bythe wind.

The device includes a telescope which is held in vertical position atthe aXisof the instrument, and through which the spot over which theinstrument is to be set can be seen, conveniently by means of an angularsight tube provided with a mirror which reflects the image in the lineof sight of the telescope. A finder is also provided for use inconnection with the telescopic plumb-bob, as well as means foradjustment to be hereinafter described. i

In the drawings, Figure l is a `vertical section showing the parts atthe head of a tripod. Fig. 2 is a vertical section at a right angle toFig. 1 of the plumb-bob proper. Fig. 8 is a side elevation, partly insection, the finder and also illustrating the use of showing the meansfor adjusting the crosshairs of the telescope. Fig. t is a section onthe line of Fig. 1.

Referring specifically to the drawings, the legs of the tripod areindicated at 6 support ing the usual lower plate 7 on which the levelingscrews 8 which support the transit or other instrument are mounted, inthe usual manner. The spindle of the transit or other instrument isindicated at 9 supporting the half ball 10 of the instrument which fitsin a socket in the shift plate 11.

The tubular brass casing 12 is threaded to the ball and forms the shellwhichcontains the bob. This casing is made in two parts screwed togetherat 13 so that the lower part of the shell may be removed. The lower endof the shell is closed by a plain, and the shell has a thin spring metaldoor 15 permitting access to the adjusting screw 16 of the telescope,the barrel of which is indicated at 17. The tube or barrel of thetelescope is made with concentric double walls with a symmetricalannular space 18 therebetween, and said space will be filledSpecification of Letters Patent. Application filed June 2, 1908. SerialNo. 436,272.

removed.

flat glass 14,

Patented Juiyao, ieee.

with lead or mercury. The telescope will be provided with the usualcross-hairs or wires 19 adjusted by capstan screws 19.

The telescope is supported in position within the shell 12 by means of alooped hanger 20 connected by a universal joint at 21 with the upper endof the shell, permitting the telescope to oscillate in the shell in alldirections. The shell has an opening or nipple at one side, as indicatedat 2Q, to receive a sighting tube 23 held in by a screw cap 24, the tubebeing coned, as 25, where it fits in the nipple. The inner end'of thesight tube is bent in line with the telescope and is provided at theelbow with a mirror 26 which reflects the image from the telescopethrough the tube. At the lower end the shell has `within the same aring` of leather 27 which acts as a buffer to prevent injury by poundingincident to the telescope swinging against the shell.

The finder attachment consists of an ordinary plumb bob 2S the string ofwhich may be attached to any one of a series of hooks 29 on the outsideof the shell 12. The plumb-bob can be quickly attached to theappropriate hook according to the height of the tripod, and it willlocate the spot over which the instrument is to be set sufficiently nearto enable the telescope to be sighted thereon. This saves considerabletime which would otherwise be necessary to iind the spot with thetelescope. j

Fig. 3 shows how the cross-hairs of the telescope may be adjusted.First, the lower portion of the shell is unscrewed at 13 and A screw cap30 is then screwed on the lower end of the telescope barrel, which isthreaded, as at 31, for the purpose. An ordinary plumb-bob 32 isconnected to the cap at the center thereof, in line with the axis of thetelescope, and the plumb-bob is set directly over a point or spot. Thecap 30 and plumb-bob 32 are then removed, after which the screws 19 maybe turned, if necessary, to adjust the cross-hairs exactly in line withthe spot. The removal of the shell allows free access to the adjustingscrews.

In use, the instrument will be approximated to the spot by means of thefinder 28, and then by sighting into the tube 23 and thus through thetelescope the instrument can be readily adjusted to bring the aXis ofthe telescope and the center of the instrument directly over the desiredspot. Inas much as the weighted telescope is contained los ii o

within the casing l2, it cannot be aected byv wind, and hence the spotfrom which the measurement of observation is taken can be very exactlylocated and the instrument will be free from the inaccuracies arisingfrom the use of an ordinary plumb-bob.

Various modifications may be made in the structure within the scope ofthe invention, v

and no limitation is implied by reason of the particular form shown.

I claim:

l. A plumb-bob comprising a casing, a telescope hung therein foroscillation in all directions, and a sight tube extending into thecasing at an angle to the telescope and having a mirror in line with thetelescope.

2. A plumb-bob comprising a closed tubular casing, a telescope thereinprovided with a weight at its lower end and suspended at its upper endfor free oscillation, and a sight tube supported in position with oneend thereof in line with the upper end of the telescope.

8. A plumb-bob comprising atubular casing, a telescope therein weightedat its lower end and hung at its upper end for free oscillation, and abent sight tube projecting through the side of the casing and having itsinner end in line with the telescope, and provided with a mirror at thebend to reflect the image to the outer end of the tube.

4. A plumb-bob comprising a telescope weighted at its lower end andsuspended in vertical position for free oscillation, with its objectivedirected downwardly, and -laterally-extending -means to sight throughthe telescope.

i 5. The combination with a support, of a plumb-bob comprising atelescope suspended in vertical position therefrom for free oscillationand weighted at its lower end, and a tubular casing surrounding thetelescope and fixed at its upper end to the support'and formed insections separable to permit access to the telescope.

6. The combination with a telescope suspended in vertical position forfree oscilla.- tion, with its objective directed'downwardly, of asymmetrical weight extending around the lower end thereof.

7. A plumb-bob comprising a telescope suspended in vertical position forfree oscillation, with its objective directed downwardly, the telescopehaving concentric double walls at its lower end forming a symmetricalannular space, and weight material in said space.

S. The combination with a support, of a plumb-bob comprising a telescopein vertical position weighted at its lower end, a hanger connected atits lower end to the telescope and projecting above the upper endthereof, a universal joint between the upper end of the hanger andthesupport, and a sighting tube extending angularly and registering at itsinner end with the telescope, and provided with a reflector.

9. rlhe combination of a plumb-bob including a telescope adapted to bedirected toward a spot desired, and a finder-bob suspended beside thetelescope, substantially as described.

10. The combination of a plumb-bob including a vertically-hanging'telescope adapted to be directed toward a desired spot, a wiiid-shieldsurrounding the telescope, and a finder bob attached to the shield anddepending therefrom.

ll. A plumb-bob comprising a telescope suspended in vertical positionfor free oseillation with its objective directed down`l wardly, andweighted at its lower end, and provided with cross-hairs and adjustingdevices therefor.

l2. rl"he combination with a tripod and a surveying instrument having avertical axis, of a plumb-bob comprising a telescope weighted at itslower end and suspended in vertical position from the support with itsaxis in alinement with that of the instrument, and with its objectivedirected downwardly, and means to sight through the telescope from theside.

In testimony whereof I aflix my signature, in presence of two witnesses.

Louis o. sLoee-ETT.

Witnesses RICHARD MURRA, ISAIAH CAMPBELL.

